Anthony at UX Movement examines scrolling versus clicking in web page design. As he notes:

As user behavior changes over time, designers need to take that into account in their designs.

What's amazing is how fast this change has been. Ten years ago — maybe as recently as five — if you designed a page the user had to scroll, many users would fail to complete a task depending on scrolling. Today scrolling has become much more of a default behavior.

Audiences are changing fast, and the rate of change seems to be accelerating. That's one of the best challenges of interaction design: you need to stay current with evolution in hardware, software, platforms, form factors, competitors, and even user behavior!